Help with resizing photos

I am trying to figure out how to make my photo size smaller than 7mb, I am trying to download a photo to ebay. I have a 7d camera and I have gone through the software that came with the camera and I am not finding anything that sounds like it will make my photo file size smaller. Where is it? What is it under? Can anyone help? I'm sure it is very simple and it is right in front of me, screaming at me. I have never played around with any of the software that came with my camera, I am computer-phobic when it comes to this stuff.
ugh!
naturac

If it is a picture you have already taken and have on the computer you can do it with your DPP software that was provided with the camera. Just go in to it, click on the picture you want, choose file, convert and save and then click on the option to resize the picture. Choose a smaller size, for instance 800 x 533 on my 1D IV pic’s is about 400kb.

In camera you can do it under the first tab in the menu, "Quality". L is the highest M is in the middle and S lowest. You can choose a lower quality setting and get a smaller file.